GSSP for Darriwilian Stage

Definition:

The base of the Darriwilian Stage is defined in a section through the
Ningkuo Shale exposed at Huangnitang, Changshan County, Zhejiang
Province, southeast China, where it coincides with the first
appearance datum of the graptolite Undulograptus austrodentatus.

Location:

The Huangnitang Section is located along an unpaved road on the riverside near
the village of Huangnitang, 3.5km southwest of the Changshan County Town of
Zhejiang Province, southeast China. The section is accessible by vehicle (in
fair weather) from the town of Erduqiao, 500m east of Huangnitang (see some photos).

Sedimentology:

Primary Markers:

First appearance of graptolite Undulograptus austrodentatus at
the base of Bed AEP 184 of the Huangnitang Section, which is 22m below
the top of the Ningkuo Formation. The first appearance of
Undulograptus austrodentatus also defines the base of the
Undulograptus austrodentatus Biozone. This biozone is divided
in a lower Arienigraptus zhejiangensis Subzone and an upper
Undulograptus sinicus Subzone.

Secondary Markers:

Correlation Events:

Graptolite FAD Undulograptus austrodentatus

Other Locations around the World:

The base of the Undulograptus austrodentatus graptolite biozone
lies just above the base of the Microzarkodina parva conodont
biozone in the North Atlantic and within the upper part of the
Histiodella altifrons Biozone in the North American
mid-continent conodont zonation. The base of the Darriwilian is coeval
with a level in the Fennian Stage of the upper Arenig of Wales.